Double-cam motor



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DOUBLE C-AM MOTOR Filed Sept. 15, 1928 5 Sheets-Sheet l Aug. 26, 1930. w DUNN 1,774,087

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' DdUBL CAM MOTOR Filed Sept. 15, 1928 3 Sheets-Sheet 3 'IIIIIIIII I;

M M Z/ZWAWMM Patented Aug. 26, 1930 UNITED STATES WILLIAM G. DUNN, OF CLARINDA, IOWA DOUBLE-CAM MOTOR Application filed September 15, 1928. Serial No. 806,256.

The object of my invention is to provide a motor having cylinders arranged opposite each other and a drive shaft having cams thereon with-which the cylinders cooperate,

'6. the motor being of simple, durable and comparatively inexpensive construction.

A further object is to provide a motor having cylindersand pistons in which the cylinders are arranged opposite each other and the pistons therein are connected with links in such a manner that the links do not oscillate but exert a straight pull from one piston to the other.

More particularly, it is my object to provide in such a motor construction a crank. ,case having cylinders connected therewith and having a drive shaft journaled in the crank case, a pair of cams being secured to the drive shaft, one cam being in alignment Withone pair of cylinders and another cam being in alignment with another pair of cylinders.

Still a further object is to provide the cams with the raised portions of one opposite the depressions on the other, wherebv while some of the pistons are moving toward the drive shaft, others will be moving away therefrom, and these two sets of pistons may be connected by links for the purpose of utilizing the force of one to move an opposite one traveling in the same direction.

Still a further object is to provide a motor construction adapted for making four cycle internal combustion engines, wherein the drive shaft rotates once during two reciprocations of a piston, whereby valve cams may be mounted directly on the drive shaft for the purpose of operating the intake and ex-.

haust valves of the motor.

Still a further objcct is to provide adjustable resilient means in fconnection with the links extending between opposite pistons for l the purpose of insuring that the pistons will at all times engage the cams and thereby provent hammering due to the pistons jumping away from the cams.

" Still a further object is to provide a motor construction in which it'is possible to have a straight drive shaft whereby such--,shaft may be of tubular construction for receiving another shaft. i

In this connection, it is more particularly my object to provide a reversible or variable pitch propeller associated with the drive shaft of the motor and to utilize the shaft within the tubular drive shaft as a means for controlling the pitch of the propeller blades whereby they may be reversed or their pitch may be varied.

Still another object is to provide on the tubular drive shaft, a head and propeller blades oscillatably mounted on said head, whereby the blades may oscillate on their longitudinal axis, the shaft within the tubular drive shaft being slidably mounted and operatively connected with said blades for causing their oscillation upon slidin movement being imparted to the sliding sha Such results can not be attained in a motor having a crank shaft because of the shape of the Y crank shaft.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my double cam motor, whereby the objects contemplated are attained as-here inafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure l is a side elevation of my improved type of double cam motor.

Figure 2 is an end elevation of the same.

Figure 3 is an enlarged, sectional view taken on the line 3-3 of Figure 1.

Figure 4 is a sectional view taken on the line 44: of Figure 3, showing the parts broken away to illustrate the water connections to the water jacket of the engine.

Figure 5 is a sectional view taken on the line 55 of Figure 3, showing parts broken away to show the valve ports in section.

Figure 6 is a sectional view taken on the. line 66 of Figure 3, illustrating the link connections between the pistons and omitting the crank case and cylinders of the engine.

Figure 7 is a perspective view of two of the links connecting the opposite pistons together and showing parts with which they cooperate in dotted lines.

Figure 8" is an enlarged, sectional view taken on the line 88 of Figure 3.

Figure 9 is a view of a propeller mounted on the drive shaft of the motor and viewed at right angles to the propeller illustrated in Figure 2 of the drawings; and

Figure 10 is an enlarged sectional view taken on the line 1010 of Figure 9.

In the accompanying drawings, I have used the reference numeral 10 to indicate a crank ease. The crank case 10 may be provided with legs 12 for the purpose of supporting the motor relative to a base or platform 14. In place of the legs 12, brackets may be provided for connecting the crank case 10 to the frame of an automobile. tractor or other vehicle.

Each side of the crank case 10 is provided with a sleeve 16 having a hub or bearing 18 formed thereon. A drive'shaft 20 is journaled in the bearings 18 and is provided with a propeller hub 108 or may be attached to a fly wheel or to various machinery to'be driven by the motor.

The bearings 18 may be of the roller or ball type, if desired.

Within the crank case 10, cams 24 and 26 are secured to the drive shaft 20. The earns 24 and 26 are provided with raised portions 28 and depressed portions 30. By referring to Figures 4 and 5 of the drawings, it will be noted that the projections 28 of the cam 24 are arranged at right angles to the projections 28 of the cam 26.

Secured to the crank case 10 are cylinders 32. The cylinders 32 are made in pairs and are provided with flanges 34 adapted't be bolted by cap screws 36 to the crank case 10. The cylinders 32 extend into the crank caseas illustrated in Figure 3 of the drawings and are provided with slots 38 through which the projections 28 of the cams 24 and 26 may rotate.

The cylinders 32 are provided with water jackets 40 whereby the engine may be watercooled from a radiator not shown on the drawings.

The water chambers 42 between the cylinders. 32 within Water ackets 40 are filled with water as indicated throughout the various viewsof thedrawings. Means for admitting water to the water chambers 42 is provided in the form of inlet passages 44 and outlet passages 46, which are shown in section in Figure 4 of the drawings.

A connection with the top of a radiator may be made with the passages 46 and with the bottom of the radiator with the' ipassages 44.

My motor, of course, may be made of the air-cooled type if desired.

.Within the cylinders 32, pistons 48 and 50 are. reciprocably mounted. The pistons 48 are inalignment with the cam 24- and the pistons 50 are in alignment with the cam 26 Bosses 52 and 54 are provided in each piston 48 and 50 for receiving a roller pin 56. A

roller 58 is mounted 011 each pin 56, and the rollers in the pistons 48 contact with the surface of the cam 24, while those in the pistons 50 contact with the surface of the cam 26.

Dividing walls 60 are provided within the pistons 48 and 50 and one of these walls is provided with a hub 62 through which the roller pin 56'extends.

On each roller pin 56 between the boss 54 and the boss or hub 62 is a block-like member 64. The block 64 is provided with a pair of openings 66 for receiving the reduced ends of links 68 and 7 O. The reduced ends of the links 68 and 7 O are indicated at 72 and are threaded as shown at 74.

The link 68 is offset adjacent the reduced ends 72 thereof as indicated at 78 and the links are offset in a similar manner as indicated at 80.

Referring to Figure 3 of the drawings, it will be seen that the links 68 and 7 O extend diagonally for connecting a piston 48 with a piston 50 which is offset therefrom.

The offsets 78 and 80 provide for the links passing each other and for them being arranged clear of the drive shaft 20 as best shown in Figure 6.

For resiliently holding the rollers 58 against the earns 24 and 26, I provide springs 82 on the ends of the reduced portions 72 of the links. Castle nuts 84 are provided on the threaded portions 74 to hold the springs in .position and for allowing an adjustment for adjusting the tension of them. Such adj ustment may be made whenever the rollers and cams become so worn that looseness of the parts results.

Since the cams 24 and 26 each have two projections 28 it will be seen that it is necessary to reciprocate a piston twice during one revolution of the drive shaft 20. Therefore since a cycle of operations for a four cycle engine is completed each two reciprocations of a piston, the cycle will be completed during one revolution of the drive shaft. This makes it possible for me to mount the valve cams 86 and 88 directly on the drive shaft 20. v

I The valve cams 86 are provided for the intake valves 90 and the cams 88 are provided for the exhaust valves 92. Each valve is actuated by a rocker arm 94 pivoted to a bracket 96 and having a socket head 98.

' A tappet 100 is provided for each rocker arm provided for the intake and exhaust valves 90 and 92 respectively. The passages 91 are shown in section in Figure 5 of the drawings.

Spark plugs 106 are screwed into the heads of the cylinders 32 for the' purpose of igniting gas within the cylinders. The timing and ignition mechanism are omitted from the drawings. The timing mechanism may be directly connected to the drive shaft 20, which rotates once per cycle of operation. Thus the necessity of timing gears is eliminated.

Since the pistons are arranged diametrically opposite each other, one cam 86 may be used for two intake valves and one cam 88 may be used for two exhaust valves, which are arranged diametrically opposite each other, as illustrated in Figure 1 of the drawmgs.

In connection with my motor, I have illustrated a propeller A of the variable pitch and reversible type. The propeller A consists of a hub 108 on the drive shaft 20 and propeller blades 112 oscillatably associated therewith. The blades 112 are provided with stems 114 which are rotatably mounted in openings 110 formed in the hub 108.

7 Heads 116 are connected to the stems 11 1 inside of the hub 108 to prevent the propeller blades from pulling out of the hub. Ball bearings may be interposed between the heads 116 and the hub to reduce friction caused by centrifugal force acting upon the blades when the propelleris rotating.

The propeller blades 112 are provided with arms 118. The drive shaft 20 is of tubular construction as best shown in Figure 10 of the drawings to receive an actuating shaft 120 slidably arranged. The shaft 120 has a cross arm 122 mounted thereon. The cross arm 122 has its ends operatively connected, by means of links 124, with the arms 118.

From the foregoing construction, it will be obvious that sliding movement imparted to the actuating shaft 120 will change the pitch of the propeller blades 112, reversing them, ifdesired, asindicated in dotted lines in Figure 9.

Instead of arm and link connections, rack and pinion or other devices could be used for accomplishing the same result. Means would be provided, ofcourse, to slide the shaft 120 and maintain it in any adjusted position but such means forms no part of my present invention, and I therefore have not illustrated it.

The propeller hub and the blade actuating mechanism are preferably covered by a cap 126'which may be formed in halves and secured to the hub 108 by screws or other.

fastening means.

Due to the construction of my motor wherein it is possible to use a straight drive shaft, it is a matter ofcomparative simplicity to form such shaft hollow and carry the blade actuating mechanism therethrough.

Various changes such as in the shape of the cams 24 and 26 or in the specific arrangement of the connecting means between opposite pistons may be made in the arrange ment and construction of the various parts of my double cam motor, without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In a device of the class disclosed, a casing, a shaft journaled therein, a cam on said shaft, a piston in alignment with and engaging said cam, a second cam on said shaft and spaced longitudinally of the shaft from said first'cam, a second piston in alignment with and engaging said second cam, a projection on one of said cams being arranged opposite a depression on the other of said cams, and means located within said casing between said cams and connecting said pistons together for causing their simultaneous movement in the same direction.

2. In a device of the class disclosed, a casing, a shaft journaled therein, a cam on said shaft, a piston in alignment with and engaging said cam, a second cam on said shaft, a second piston parallel to the first piston and .in alignment with and engaging said second cam, a projection on one of said camsbeing arranged opposite a depression on the other of said cams, and a link located within and extending diagonally from one of said pistons to the other for operatively connecting the two pistons together.

3. In a device of the class disclosed, a casing. a shaft journaled therein,-a cam on said shaft, a piston in alignment with and engaging said cam, a second cam on said shaft, a second piston in alignment with and engaging said second cam, a projection on one of said cams being arranged opposite a depression on the other of said cams, and a link connecting the two pistons together, said link being adjustably arranged as to length for the purpose of changing the distance between the portions of the pistons which engage the cams whereby compensation for-wear is provided.

.4. In a device of-the class described, a casing, a pair of cylinders, a shaft, a piston slidable in one of said cylinders, a second the pistons.

relation to said shaft, a diagonally extending resilient means within said casing for connecting the pistons together for causing their simultaneous movement, and means engaged by the pistons for rotating said shaft upon reciprocating movement of the pistons, said means comprising cams having a projection on one arranged opposite a depression on the other, said resilient means-being arranged between said cams and straddling said shaft.

6. In a motor construction, a casing, a shaft journaled therein, a pair of cylinders formed in said casing on opposite sides of said shaft and staggered relative to each other, pistons in said cylinders provided with rollers, cams on said shaft arranged in alignment with the respective pistons, and link means having its ends operatively connected with the two pistons and its central portion arranged between said cams.

7. In a motor construction, a. casing, a shaft journaled therein, a pair of cylinders formed in said casing on opposite sides of said shaft and staggered relative to each other, pistons in. said cylinders, said pistons each having a roller pin, a roller on each pin, cams on said shaft arranged in alignment with the respective pistons, and link means within said casing and extending diagonally between said pistons for operatively connecting them together;

' 8. In a motor construction, a casing, a shaft journaled therein, a pair of cylinders formed in said casing onopposite sides of said shaft and staggered relative to each other, pistons in said cylinders, said pistons each having a roller .pin, a roller on each pin,

cams on said shaft arranged in alignment ing said second cam, a projection on one of said cams being arranged opposite a depression on the other of said cams, and means connecting said pistons together for causing their simultaneous movement in the same direction, said means including resilient means to keep said pistons in engagement with said cams.

11. In motor construction, a casing, a shaft journ'aled therein, a pair of cylinders formed in said casing onopposite sides of said shaft and staggered relative to each other, pistons in said cylinders, said pistons each having a roller pin, a roller on 'each pin,

cams on said shaft arranged in, alignment with the respective pistons, blocks on said roller pins and a link having its ends slidably mounted through said blocks, springs and nuts on said links, said springs being interposed between said blocks and said nuts.

12. In a motor construction, a pair of radially opposite cylinders, a pair of opposed pistons in said cylinders having pins extending through the pistons transverse to the axes thereof, and means for connecting said pistonsfltogether comprising a block on each pin and a link having its ends extending through said blocks.

13. In a motor construction, a pair of radially opposite cylinders, a pair of opposed pistons, one in each cylinder and each having pins extending therethrough transverse to the axes of the pistons, and means for connecting said pistons together comprising a block on each pin and a link having its ends extending through said blocks, nuts arranged on said link adjacent the extreme ends thereof and springs on said link interposed between said blocks and said nuts.

Des Moines, Iowa, September 5, 1928.

WILLIAM G. DUNN.

with the respective pistons whereby the cams are also staggered, blocks on said roller pins and a link within said casing and having its ends secured to said blocks, said link having its central portion arranged between said cams.

9. In a motor construction, a casing, a shaft j ournaled' therein, a pair of cylinders formed in said casing on opposite sides of said shaft and staggered relative to each other, pistons in said cylinders, said pistons each having a roller pin, a roller on each pin, cams on said shaft arranged in alignment with the respective pistons, blocks on said roller pins and a link having its ends slidably mounted through said blocks, said link being provided with threaded adjusting means.

10. In a device of the class disclosed, a casing, a shaft journaled therein, a cam on said shaft, a piston in alignment with and en aging saidcam, a second cam on said sha a second piston in alignment with and engag- 

